1. Field of the Invention
The present position pertains to remote sensing and, more particularly, to remotely sensing the position of an object.
2. Description of the Related Art
Remote sensing technologies continue to become more common as technological capabilities continue to improve. Remote sensing typically revolves around the collection of energy radiated from or reflected by an object of some kind, detecting the collected energy and converting it to some kind of usable data, and then processing the data that signal contains. The data may be processed to, for instance, determine the object's position or even identify it. In some applications, this information can be employed to take some further action, such as to target the object for some kind of attention or to position oneself relative to the object.
However, the quality of the collection effort can limit the effectiveness of even state of the art detection, conversion, and processing. Poor, incomplete, or misleading data, no matter how well it is processed, can yield incorrect results. This problem is particularly acute in military contexts, where obfuscation, camouflage, and countermeasure techniques are routinely used to defeat remote sensing. Not only are these types of techniques commonly employed, such use is typically very aggressive since the stakes can quite literally mean life or death for a combatant.
Consider, for instance, a situation commonly portrayed in popular culture, in which a missile is launched at an aircraft to destroy it. Assume, for purposes of this example, that the missile has remote sensing capabilities. The missile might remotely sense the position of the aircraft so that it can home in on the aircraft. The aircraft will typically try to avoid such an outcome once it becomes aware of the missile's threat. The aircraft may employ countermeasures to confuse the missile's remote sensing capability. For instance, the aircraft may fly directly into the sun, or shoot off flares.
Both of these countermeasures flood the environment the missile is remotely sensing with energy. Typically, the missile will attempt to locate the position of the aircraft by determining the center, or “centroid”, of the remotely sensed energy, which it assumes represents the aircraft. This approach works quite well when the aircraft is the only significant energy source that the missile can see. Countermeasures, however, jeopardize the validity of the assumption. When the countermeasures flood the environment with energy, and when the countermeasure is not aligned with the aircraft in the missile's line of sight, additional energy shifts the target away from aircraft and toward the countermeasure. If the energy emanating from a countermeasure is strong enough, and if the countermeasure is sufficiently distanced from the aircraft, it can shift the centroid far enough away from the aircraft that the missile will miss the aircraft as it homes on the centroid.
Similar types of problems may also be encountered in much less dramatic, civilian contexts. Consider a situation in which one might wish to determine the position of an object using a laser rangefinder. The position of the object, or the time of day, or both might create a situation where the Sun creates an obstacle for the laser rangefinder in much the same way that countermeasures confuse the missile. While the consequences are much less extreme, the problem nonetheless remains.
The present invention is directed to resolving, or at least reducing, one or all of the problems mentioned above.